L-乳酸熔融缩聚的工艺研究

为降低聚乳酸的成本、扩大其应用范围,以L-乳酸为原料,通过熔融缩聚法合成了聚L-乳酸(PLLA),考查了催化剂种类、催化剂用量、聚合温度和聚合时间等对PLLA分子量、产率和颜色的影响,摸索出最佳反应条件。熔融缩聚反应的最佳工艺条件为:SnCl2作为催化剂,用量为0.4%,聚合温度175℃,聚合时间8 h,合成的PLLA分子量可达6.2万,产率为72.8%。此工艺提高了聚合物分子量和产率,降低了聚乳酸材料的应用成本,拓宽了聚乳酸的应用范围。

Study on melt polycondensation of L-lactic acid

In this paper,the direct melt polycondensation method with L-lactic acid was used so as to reduce the cost of polylactic acid and to expand its application.The influences of catalyst types,catalyst quantity,reaction temperature and time,etc.on molecular weight,yield and color of PLLA were investigated.And the best reaction conditions were found.The best conditions of melt polymerization were as followed: SnCl2 was chosen as the appropriate catalyst and its usage was 0.4%,175 ℃,reacting 8 h,the viscosity average molecular weight and the yield of PLLA reached 6.2×104 and 72.8%,respectively.In the paper,the molecular weights and the yields of PLLA were increased,the application cost of PLLA was reduced and the application areas were widened.